First of all - great site!I'm a student pilot so its great to be able to practice listening to ATC comm.

However, quite a few of the feeds have a fair amount of hum.

Best would of course to be to eliminate this at the source, but thats not always possible (computers & audio are nevereasy..), have you guys looked into running the sample stream through a digital notch filter ? It should not be that compute intensive, but of course I haven't tried anything nor do I know more of what you do to capture the audio.

Also - I was thinking it would be interesting to present a snapshot of the waveform (say for the last 10 minutes) when selecting which station to be able to quickly pick one that has the most activity.

We use a variety of UNIX and Linux servers and Icecast for streaming. I don't see any easy way of integrating this into Icecast, at first glance. Sox works great, but the problem has always been finding a place to plug it in.

This happens on so few streams that it would be hard to justify the work required to do this.

Well, maybe I'm picky, but on the class C airfeeds,all these have hum to some extent:PANC, KBTV, KLFT, KMKE, KLEX, KMHTThats 6 out of 8 (working) feeds!

So on the feeder site, how do you read the audio device ?When you encode to mp3, do you take directly from the device ? If so then you could simply run sox in between and have lame (or whatever libshout uses to encode) encode the filtered output ?

I'm willing to try try setting up a test feeder site (with hum removal) to try it out if you don't have time for it.

Quote from: dave

We use a variety of UNIX and Linux servers and Icecast for streaming. I don't see any easy way of integrating this into Icecast, at first glance. Sox works great, but the problem has always been finding a place to plug it in.

This happens on so few streams that it would be hard to justify the work required to do this.

But - after you mentioned using an equalizer I checked thexmms plugins - and there is actually a 'sox' plugin! Unfortunately it was missing the bandreject filter, will check the package to see if its possible to add it.

Thanks!

Quote from: dave

98% of the feeder sites run Stream Transcoder on Windows.

Another way to try and reduce it, which seems to work OK, is to adjust the equalizer on your MP3 player (Winamp has one, not sure about the rest).YMMV.